Above you can see the setup; the RCT715 hooked up to a 10000mah backup (GETIHU BG-140) on a 4 hour ride. Set for continuous camera recording, and flash changing as cars approach. At the end of the ride the power bank had used up 17% of its capacity, while the RCT715 stayed at 100% charge.
My biggest issue is with the mounting of the RCT715. The seatstay mounting isn't secure enough; it will try to move inward towards the wheel on bumpy pavement. Not a good thing. Going to try to figure out how to use something that clamps on the seat mast and drop down, to put it "over" the rear brake.